ABSTRACT Introduction It has a long history to employ Macleaya cordata (Willd.) R. Br. (Papaveraceae) for the treatment of a variety of diseases in China. Chelerythrine, one of the major of M. cordata with detoxifying and anti-inflammatory effect, is reported to combat bacteria and fungus. This work aims to explore the effect of chelerythrine against fluconazole-resistant C. albicans and also illustrate its potential mechanism. Methods The microdilution method, following CLSI-M27-A3 was used to evaluate the effect of chelerythrine against fluconazole-resistant C. albicans. Meanwhile, biofilm viability was assessed by XTT assay and cell morphology was observed by inverted microscope. RT-qPCR and confocal laser scanning microscope were employed to detect the mRNA expression and DCFH-DA staining, respectively. Fluorescence intensity was quantified by flow cytometry. Results The total alkaloids extract of M. cordata significantly inhibited the viability of C. albicans, concentration of which in 64 μg/mL presented to 40% inhibitory effect . In addition, the MIC 80 for chelerythrine was 8 μM, whereas chelerythrine in 4 μM inhibited biofilm formation by 47.7%. Further studies revealed that chelerythrine reduced the hydrophobicity of cellular surface, inhibited hyphal growth, downregulated the expression of genes related to cAMP pathway, increased cellular permeability and promoted the production of reactive oxygen species (ROS). Conclusion Chelerythrine inhibited biofilm formation by decreasing CSH and inhibiting the cAMP pathway. Chelerythrine increased cellular permeability and promoted the production of reactive oxygen species, which leads to the cell death of fluconazole-resistant C. albicans .
Hong Ni,Zhongzhao Guo,Yue Wu,Jie Wang,Yang Yang,Zilu Zhu,Deheng Wang
It is generally accepted that Cyclooxygenase-2 (COX-2) is activated to cause inflammation. However, COX-2 is also constitutively expressed at the postsynaptic dendrites and excitatory terminals of the cortical and spinal cord neurons. Although some evidence suggests that COX-2 release during neuronal signalling may be pivotal for regulating the function of memory, the significance of constitutively expressed COX-2 in neuron is still unclear. This research aims to discover the role of COX-2 in memory beyond neuroinflammation and to determine whether the inhibition of COX-2 can cause cognitive dysfunction by influencing dendritic plasticity and its underlying mechanism. We found COX-2 gene knockout (KO) could significantly impact the learning and memory ability, cause neuronal structure disorder and influence gamma oscillations. These might be mediated by the inhibition of prostaglandin (PG) E2/cAMP pathway and phosphorylated protein kinase A (p-PKA)-phosphorylated cAMP response element binding protein (p-CREB)-brain derived neurotrophic factor (BDNF) axis. It suggested COX-2 might play a critical role in learning, regulating neuronal structure and gamma oscillations in the hippocampus CA1 by regulating COX-2/BDNF signalling pathway.
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